Arrangement for comminuting scrap in ribbon or strip form from, for example, steel plate

ABSTRACT

Apparatus for comminuting scrap in ribbon or strip form from, for example, steel plate into short sections attains a reduced-noise comminuting arrangement of simple construction, and also processes materials of different thicknesses without any readjustment, the apparatus having with two rotors which are driven synchronously in opposite directions and each having knives which project at the periphery of the rotors and which, when they met, carry out a shearing cut, and moreover with two mutually meshing toothed wheels for driving the knife rotors mounted on shafts so that they cannot twist and with a fixed distance between axes, one of the toothed wheels being seated on the shaft of the first rotor and driving this shaft while the other is freely rotatably mounted on the shaft belonging to the second rotor and drives this shaft over a driving mechanism elastically supported in the direction of rotation.

The invention relates to an arrangement for comminuting scrap in ribbonor strip form, for example, from steel plate, into short sections. Suchscrap or waste strips are obtained, for example, in splitting, trimming,stamping, etc. installations.

Previously known comminuting arrangements for such ribbon- orstrip-shaped scrap have a rotor, which is equipped at its periphery withseveral tools, for example, with four knives, and which works togetherwith a stationary counterknife. The scrap is comminuted into shortsections, in each case by knocking off the section from the ribbon orstrip. This is associated with much noise and therefore frequently, nolonger permitted by the authorities today from the point of view ofnoise protection. In these cases, there has already been a changeover torolling up and tying off the ribbons or strips, obtained as scrap, andto dispose of them as so-called scrap coils. This is, however,associated with a considerable expense for equipment, handling, storageand transport for the plants, in which this scrap is obtained.

It is therefore a primary object of the invention to provide anoise-reduced comminuting arrangement for the ribbon- or strip-shapedscrap in question, which moreover, while of simple construction, canalso process materials of different thickness without any readjustment.

The comminuting arrangement of the invention operates very quietly owingto the fact there no longer is any knocking off or chopping off, butrather a shearing off with a shearing cut. An almost silent operationcan be achieved by means of the advantageously provided holding-downcushion. No readjustment of the knives is required for differentmaterial thicknesses, for example, from 0.5 to 5 mm, since the cuttinggap is adjusted automatically to the respective ribbon thickness.Moreover, owing to the fact that the knives unroll in oppositedirections and produce a shearing cut, they sharpen one another so thattheir serviceable life is long. Moreover, the knives can be exchangedand reground (circular grinding machine) easily. The knives need not beadjusted individually; rather, by loosening the conical adapter bushingand turning the first rotor, an adjustment equally accurate for allknives is achieved.

The object of the invention is described in greater detail below bymeans of an example of the operation shown in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially cut away view of the comminuting arrangement takenapproximately along the line I--I of FIG. 2;

FIG. 2 is a cross sectional view taken approximately along the lineII--II of FIG. 1;

FIG. 3 is a partial view similar to that of FIG. 1 but on an enlargedscale of a modified embodiment; and

FIG. 4 is a cross sectional view taken approximately along the lineIV--IV of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In a housing part or support means 1, two shafts 2 and 3 are rotatablysupported with a fixed distance between axes. On the shafts 2, 3, whichare disposed parallel to one another and preferably, as shown,vertically on top of one another with their axes in horizontalalignment, two disk-shaped rotors 4 and 5 are mounted so that theycannot twist, the upper shaft 2 of the drawing carrying the first rotor4 and the lower shaft 3 of the drawing the second rotor 5. The tworotors 4, 5 are disposed coplanar to one another and are drivensynchronously to rotate in opposite directions (in the directions of thearrows of FIG. 1).

The two rotors 4, 5 are driven over two meshing toothed wheels or gearwheels 6 and 7, of which the toothed wheel 6, which drives the firstrotor 4, is seated on shaft 2 so that it cannot twist and is drivendirectly by an electric motor or hydraulic motor or is coupled to anddriven by the equipment producing the scrap strip. For securing thetoothed wheel 6 on shaft 2, an easily detachable conical adapter bushing8 is preferably provided, so that, after this bushing is loosened, therotor 4 can be adjusted in the circumferential direction relative to therotor 5 and also fixed once again in the set position rapidly andeasily.

The toothed wheel 7, which meshes with the toothed wheel 6 and drivesthe second rotor 5, is mounted freely rotatably on the shaft 3 anddrives this over a driving plate 9, which is connected with the shaft 3so that it cannot twist. For this purpose, axially projecting bolts 10are provided at a side face of the toothed wheel 7. These bolts 10 reachthrough the openings 11 in the driving plate 9, which is coaxial withtoothed wheel 7, with sufficient play, so that limited relative movementwith respect to the common direction of rotation can take place betweenthe toothed wheel 7 and the driver plate 9 and thus between the toothedwheel 7 and shaft 3. Over springs 12, which at one end act upon bolt 10and at the other end act upon the stop bolt 13 projecting from thedriving plate 9, the toothed wheel 7 and the driving plate 9 aremutually braced and supported elastically in such a manner, that adisplacement in the angle of rotation, coming from the rotor 5 in amanner yet to be described below in greater detail and the thustriggered relative movement between the driving plate 9 and the toothedwheel 7 in each case are absorbed elastically and compensated for.

At the periphery of the first rotor 4, several flat knives 14 aredetachably mounted, for example, screwed on with locking screws 15 andpressure screws 16. Before each flat knife 14 in the direction ofrotation, there is mounted advantageously in each case a holding-downcushion 17, which consists of rubber, plastic, etc. and therefore iselastic, which has the width or thickness of the rotor 4 and forms acircumferential area of the rotor 4 before the respective flat knife.

At the periphery of the second rotor 5, a number of circular knives 18,corresponding to the number of flat knives 14 on the first rotor 4, aredetachably mounted, for example, by means of countersunk socket-headscrews 19. The circular knives 18 form a cutting surface 20, which runsat right angles to the radius of the rotor 5 and which, together withthe cutting edge 21 of the flat knife 14 on the rotor 4 runningtransversely to the direction of rotation, produces a closing cuttinggap and thus a shearing cut for shearing off a scrap strip 22 in thegap. To achieve a pulling shearing cut, the cutting surface 20 of theround knives 18, as can be seen from FIG. 2, is provided with aninclined gradient converging to the axis of the rotor 5, so that acutting angle α of, for example, 8° results between the cutting edge 21of the flat knife 14 and the cutting surface 20 of the circular knife18.

Advisably, four flat knives 14 are provided at the first rotor 4 and,correspondingly, also four circular knives 18 at the second rotor 5,which in each case act in concert with one another, so that four cutstake place for each revolution of the knife rotors 4, 14 and 5, 18.Depending on the diameter of the knife rotors and the desired length ofthe sections severed from the scrap ribbon or strip, the rotors may alsobe equipped with a larger or smaller number of knives, the number offlat knives and the number of circular knives of course being the same.

The circular knives 18 on the second rotor 5 are provided at the sidewith stop supports protruding over their cutting surface 20, whichensure that the associated flat knife 14 is supported at the circularknife before and during the cutting operation and moves with a relativemotion along the rear side of the circular knife, when the two knives14, 18, as a consequence of the rotors 4, 5 revolving in oppositedirections, meet in motion in the same direction. In the versions ofFIGS. 1 and 2, the stop supports are formed by semicircular fixedprojections 23 which stand up above the cutting surface 20 of thecircular knives 18 and along which the associated flat knife 14 withlateral projections 24 slides regionally before and during the cuttingoperation. In the version of FIGS. 3 and 4, the stop supports are formedby rollers 25, which are mounted freely rotatably at the sides of thecircular knives 18 and on which the associated flat knife 14 with thelateral projections 24 rolls off, so that there is no sliding frictionat the stop supports. The rollers 25 may consist of steel or also of astrong plastic, which brings about a further damping of noise.

The arrangement functions as follows. The scrap ribbon 22, which is tobe comminuted, is introduced over an appropriately provided feederfunnel 26 aligned approximately horizontally between the two kniferotors 4, 14 and 5, 18 and drawn in by their rotation between the knives14, 18 and then sheared off in a shearing cut by the flat knife 14 ofthe first rotor 4 working against the circular knife 18 of the secondrotor 5, as described above. The displacement in the angle of rotationbetween the rotor 4 and the rotor 5, resulting from the flat knife 14running up against the circular knife 18, is absorbed and compensatedfor by the elastic support between the toothed wheel 7 and the drivingplate 9, so that no die clearance arises between the two knives 14, 18.Moreover, due to the elastic compensation of the displacement in theangle of rotation arising as the flat knife 14 of the first rotor 4comes up against the circular knife 18 of the second rotor 5, scrapribbons 22 ranging in thickness from, for example, 0.5 to 5 mm, aresheared off without requiring a resetting of the knives at the rotors.

Due to the shearing cut that takes place, and in conjunction with theholding-down cushions 17, which are disposed ahead of the the flatknives 14 at the first rotor 4, which serve to move up the scrap stripas well as to hold down scrap section, an almost soundless cut isproduced.

I claim:
 1. Apparatus for comminuting scrap in ribbon form comprising asupport means, first and second shafts rotatably mounted on said supportmeans, a first rotor fixed to said first shaft, a second rotor fixed tosaid second shaft, first knife means mounted on and extending to theperiphery of said first rotor, second knife means mounted on andextending to the periphery of said second rotor such that upon rotationof said first and second rotors synchronously in opposite directions,said first and second knife means are moved to a juxtaposed and mutuallycooperable position to effect cutting of said scrap, a first gear wheeldisposed on said first shaft, first mounting means mounting said firstgear wheel on said first shaft to preclude relative rotation betweensaid first gear wheel and said first shaft, a second gear wheel disposedon said second shaft so as to be rotatable relative to said secondshaft, and an elastic driving means between said second gear wheel andsaid second shaft which elastically connects said second gear wheel tosaid second shaft.
 2. Apparatus according to claim 1, wherein aplurality of said first knife means are equally spaced about theperiphery of said first rotor and a like number of second knife meansare equally spaced about the periphery of said second rotor. 3.Apparatus according to claim 1, wherein said first knife means comprisesa flat knife and said second knife means comprises a circular knife. 4.Apparatus according to claim 3, wherein said circular knife has aninclined cutting surface which is inclined relative to the axis of saidsecond rotor.
 5. Apparatus according to claim 4, wherein said circularknife has side stop supports projecting from the sides of said cuttingsurface and projecting radially outwardly of said cutting surface suchas to be disposed on either side of said flat knife when in saidjuxtaposed and mutually cooperable position.
 6. Apparatus according toclaim 5, wherein said side stop supports are in the form of semicircularprojections.
 7. Apparatus according to claim 3, wherein said circularknife comprises stop supports in the form of rollers rotatably mountedon said circular knife, said flat knife rolling off of said rollersbefore and during the cutting operation.
 8. Apparatus according to claim1, wherein said elastic driving means comprises a driving plate fixed tosaid second shaft, said driving plate being coaxial with said secondgear wheel, a plurality of spaced openings in said driving plate, aplurality of projections projecting laterally from said second gearwheel and projecting into said openings to provide for limited relativerotational movement between said driving plate and said second gearwheel, said elastic driving means further comprising spring meansextending between said projections and said driving plate such that saidspring means provide an elastic connection between said driving plateand said second gear wheel.
 9. Apparatus according to claim 8 furthercomprising second projections projecting laterally from said drivingplate, said spring means being connected to said second projections. 10.Apparatus according to claim 1, wherein said first knife means comprisesa flat knife and a resilient holding-down member juxtaposed to and aheadof said flat knife in the direction of rotation of said first rotor. 11.Apparatus according to claim 1, wherein said first mounting meanscomprises a conical adapter bushing for adjusting the position of saidfirst gear wheel on said first shaft.
 12. Apparatus according to claim 1further comprising a feeder funnel for aligning strips of scrap beingfed to said first and second rotors.